I would like to add that while the gym is a great resource as a beginner, as you grow as a player into a competitive powerhouse you will find that a select few of the elite players in pokemon actually post on here.
also, the cards listed to be the best are, mostly, opinion.
some are undeniably good.
pokemon collector
pokemon communication
bebes search
luxury ball
uxie
azelf
most of the SP trainers. etc.
I used to play magic when i was younger, and im still pretty young now, but decks such as the old "Zoo" are highly popular and easy to play. while more strategic decks tend to have better showing at tournaments.
hand control and disruption can be improtant and a good part of strategy (ex: sablelock)
but high power/speed can be seen as solid (ex: kingdra)
while technical and tricky decks are also good (ex: luxchomp)
and field control is much more important than card advantage in pokemon, with cards that can draw ridiculous amounts being commonplace, card advantage is almost null at points.
there was a deck, and while it may still exist it lost some vital cards, based around Gyarados SF, which, with some setup, could do 90-110 damage for no energy. it was good because while you KO'ed your opponent, they lost energy attachments, yet when they KO'ed you, you lost just the gyarados, which could be easily brought bac with trainers.
If you want to PM me with questions I'd be cool with that, since I love helping new players and you seem cool, and maybe Pokegm as a community can help build you up to be a high caliber player.
best of luck